Cops yesterday discovered a body in a freshly dug grave in a Queens back yard, and are investigating whether it belongs to the missing 60-year-old retiree who lives there.

Former mailman Frank Soucie — who lives with his girlfriend and her adult son — was reported missing from the Ridgewood building about a week ago, police said. Yesterday, a neighbor saw someone tossing out an unusually large bag and called cops. Officers found a charred sleeping bag in the trash. They also discovered ammonia and gloves on the roof — and a mound of freshly dug dirt in the back yard.

“[The corpse] was in the fetal position. He had boots on,’’ said a neighbor, Sarah Martinez.